In a wide variety of food products, fat is used as a major component not only because of its nutritional importance, but also because of its wide range of functional properties. Fat has been found to be an ingredient which may be suitably combined with a wide variety of dry ingredients, often powdery ingredients. In these applications the fat will mostly be added in the liquid state or under shortenised form to a homogeneous mass of the dry ingredients. In other applications fat is combined with water and some dry ingredients. A homogeneous product is obtained when emulsifying the fat with the water.
One of the most important functional properties of the fat is its effect on the structure of the final food product in which it is incorporated. The structure of a product depends on both its recipe—i.e. the amount and nature of the fat and the other ingredients—and on the process according to which the product is made. For example processing steps such as emulsification, heating, tempering, influence the structure of the product obtained.
An example of a food product where the nature of the incorporated fat has a prominent effect on the structure is chocolate. Chocolate has a hard structure because of the incorporation of cocoa butter which is a hard fat; confectionery creams like medium hard sandwich creams contain a medium hard fat; spreads for example chocolate spreads, contain high amounts of liquid oil to obtain the typical soft and spreadable end product. In each of these examples fat is combined with at least one powdery ingredient (for example sugar, milk powder, cocoa powder, etc.).
Depending on the intended application and the final structure envisaged for the application, a fat will be chosen with a specific Solid Fat Content (SFC) as a function of temperature. Typical SFC-profiles for different applications are illustrated in EP-A-739,589 table 22a. The SFC-profile depends mainly on the nature of the fatty acids making up the (tri)glycerides of the fat, on the triglyceride composition, and on the method used to solidify the fat—in particular the crystallisation time and temperature, whether the product has been subjected to tempering or not, etc. Whether a fat at a certain temperature is liquid or solid is determined not only by the chain length of the fatty acids, but in particular by the type of fatty acid, i.e. whether it is saturated or non-saturated, and in case of non-saturated fatty acids, the type of isomer, cis or trans. For products that need a rather firm structure, usually a fat with a rather high SFC-profile will be selected, meaning that the fat will have a quite high amount of saturated fatty acids and/or trans isomers of non-saturated fatty acids. Saturated fatty acids (SAFA) are abundantly present in natural fats like cocoa butter, palm oil, palm kernel oil, coconut oil, tallow, etc. Trans fatty acids (TFA) of natural origin are mainly found in ruminant fats. Natural vegetable oils and fats do not contain this trans isomer. Although TFA are unsaturated fatty acids, their structure and melting profile is much closer to that of the corresponding saturated fatty acid than to that of their cis-form.
Although a wide range of hard structural fats suitable for producing structured products is naturally available, there is still a big need for fats with a solid structure and a major fatty acid chain ranging from C14 to C20. To obtain such fats, hydrogenation of liquid oils like soy, rapeseed, sunflower, groundnut oil to hard fats has been widely used. Hydrogenation, also called “hardening” of the liquid oils and fats, is usually carried out in the presence of a catalyst. However, the hydrogenation not only involves conversion of unsaturated fatty acids into saturated fatty acids, but also conversion of cis-unsaturated fatty acids into trans-isomers. Both the increased amount of SAFA and TFA contribute to the increased hardness after hydrogenation. Although from a functional point of view the use of a fat with a rather high amount of SAFA and/or TFA will be recommended to achieve the desired structure, from a nutritional point it is highly preferred to limit the concentration of these fatty acids. It has been demonstrated that consumption of SAFA and TFA increases the risk to the occurrence of cardiovascular diseases. Therefore official instances, like WHO, have issued maximum recommended levels of daily intake of SAFA and TFA. Studies on the consumption patterns of fats in food, like the so-called Transfair study, conducted in a number of European countries, indicate that the daily intake of both SAFA and TFA is far too high, in a large number of countries.
For certain food products, like chocolate, it is desirable that they show a very hard and snappy structure, and at the same time completely melt at body temperature, without leaving a sensation of waxiness in the mouth. In chocolate, these remarkable characteristics are obtained by the use of cocoa butter. Cocoa butter advantageously is a natural, non-hydrogenated fat. However, it has the disadvantage that it contains about two thirds of saturated fats, which is easily understandable from its typical symmetrical SUS-triglyceride structure (S=Saturated fatty acid; U=Unsaturated fatty acid).
There is thus a need for food systems and food products, with a hard structure comparable to chocolate, wherein the glycerides present in the product contain a limited level of SAFA and/or TFA, whereby the products exhibit the typical properties of chocolate, in particular a good melting in the mouth, snap and sufficient heat resistance. There is also a need for glyceride compositions which enable producing food products with such hard structure, but with a limited level of SAFA and/or TFA, and to a process for producing such compositions.